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    <title>Document</title>
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<body>

    <script>

        // 链式操作
        //    本质：返回了同类型数据



        let arr = [1, 2, 3, 4, 5];

        // arr.slice(2, 5).concat([6, 7, 8]).push(9).push(10);


        let str = 'hi';

        // str.replace('h', 'w').substring().split('').replace('i', 'e')


        // fn()()()

    </script>

</body>

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